Method and system for computing fourier series coefficients for mask layouts using FFT
First Claim
1. A method for computing a Fourier series representation of a mask transmission function for a print simulation of a lithography mask used in a manufacture of lithography masks, the method comprising the steps of:
- sampling at least one polygon of a mask pattern of the lithography mask to obtain an indicator function defining the at least one polygon using a number of pixels;
performing a Discrete Fourier Transform (DFT) on the indicator function to obtain coefficients of the DFT; and
scaling, using a computer device, the coefficients of the DFT to obtain exact coefficients of a Fourier series that represents the mask transmission function,wherein the mask pattern comprises at least one tile, wherein the at least one tile comprises the at least one polygon.
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Abstract
A method and system for computing Fourier coefficients for a Fourier representation of a mask transmission function for a lithography mask. The method includes: sampling a polygon of a mask pattern of the lithography mask to obtain an indicator function which defines the polygon, performing a Fourier Transform on the indicator function to obtain preliminary Fourier coefficients, and scaling the Fourier coefficients for the Fourier representation of the mask transmission function, where at least one of the steps is carried out using a computer device.
13 Citations
20 Claims
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1. A method for computing a Fourier series representation of a mask transmission function for a print simulation of a lithography mask used in a manufacture of lithography masks, the method comprising the steps of:
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sampling at least one polygon of a mask pattern of the lithography mask to obtain an indicator function defining the at least one polygon using a number of pixels; performing a Discrete Fourier Transform (DFT) on the indicator function to obtain coefficients of the DFT; and scaling, using a computer device, the coefficients of the DFT to obtain exact coefficients of a Fourier series that represents the mask transmission function, wherein the mask pattern comprises at least one tile, wherein the at least one tile comprises the at least one polygon. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system, comprising:
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means for sampling at least one polygon of a mask pattern of a lithography mask to obtain an indicator function defining the at least one polygon using a number of pixels; a computer device including means for performing a Discrete Fourier Transform operation on the indicator function to obtain coefficients of a Discrete Fourier Transform; and means for scaling the coefficients of the Discrete Fourier Transform to obtain exact coefficients of a Fourier series that represents a mask transmission function for the lithography mask, wherein the mask pattern comprises at least one tile, wherein the at least one tile comprises the at least one polygon. - View Dependent Claims (13, 14, 15, 16, 17, 20)
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18. A method, comprising the steps of:
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sampling at least one polygon of a mask pattern of a lithography mask to obtain an indicator function defining the at least one polygon using a number of pixels; performing a discrete Fourier transformation on the indicator function to obtain coefficients of a discrete Fourier Transform; and scaling, using a computer device, the coefficients of the discrete Fourier Transform to obtain exact coefficients of a continuous Fourier series that represents a mask transmission function, wherein the mask pattern comprises at least one tile, wherein the at least one tile comprises the at least one polygon; using the continuous Fourier series to obtain a print simulation of the lithography mask; and using the print simulation for manufacturing at least one of an integrated circuit and a lithography mask. - View Dependent Claims (19)
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Specification